


I'd Kill For You

by qwanderer



Category: Voltron: Legendary Defender
Genre: AU, Dark!Keith, Dead Dove: Do Not Eat, Horror AU, M/M, Sheith Halloween Exchange 2018, Yandere!Keith, dark!shiro, even when I do MCD it's fluffy, killer!shiro, never thought you'd see me use THAT tag did you, unhealthy relationship, yeah I don't usually do this so it's probably comparatively soft
Language: English
Status: Completed
Published: 2018-10-27
Updated: 2018-10-27
Packaged: 2019-08-08 13:55:21
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 4,368
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16430690
Author URL: https://archiveofourown.org/users/qwanderer/pseuds/qwanderer
Summary: "Then we kill," Keith said, voice low and steady, "to save each other. You think you can do that?"Shiro looked at Keith. Keith, who was fire that consumed all of Shiro's doubts and worries. Keith, who made everything sound simple when he spoke. Keith, who had always been worth breaking rules for."For you?" Shiro answered. "Of course."





	I'd Kill For You

**Author's Note:**

> Written for the Sheith Halloween Exchange 2018, for msgod. Beta'ed by [noir_luna](https://archiveofourown.org/users/noir_luna/)!
> 
> tbh I'm not super familiar with the slasher genre of films/games, and don't usually write this kind of fic at all, but I got this prompt and was like "Okay so basically Empok Nor but with sheith smut, right? Can do" and I hope it's worked out okay. It was definitely fun to write!
> 
> also I thought people might be interested to know that I was listening to the Shawshank Redemption score while editing this today and it felt incredibly apropos.

The Komar had brought them here, Shiro realized, distantly and far, far too late. 

The Komar craved death, craved the quintessence of living beings, and it had reached out through the universe to find a killer. To find the Champion of the Galran gladiator pits. The monster that inhabited the core of this isolated space station had reached out into the universe and chosen Shiro, plucked him from his place in Voltron and brought him here. 

The only way out of here was to kill. 

* * *

It had begun when they'd visited the Blade of Marmora base the second time, to share all of their newest intel. The Blades had only asked for Keith, but he refused to go without Shiro. He crossed his arms stubbornly, planting his feet, refusing to step up into Red. 

“I won’t go,” Keith said. “Not without you.” 

"You're one of them," Shiro reminded Keith. "They might not trust anyone fully, but they trust you a lot more than me." 

Keith's eyes flashed. "If the Blade of Marmora wants to deal with Voltron, they'll need to deal with the Black Paladin. I don't want to be one of them if it means leaving behind the human parts of my life." 

"Okay," Shiro said. 

He understood. Some days he felt like the human parts of his life were already long gone. 

* * *

Both of them walked through hundreds of meters of dramatic, dimly lit corridors, getting further into the base than they ever had the first time. And then they were sat down in front of a console, and told to pore over the massive amounts of data that the Blade had collected about Galra operations in recent months. 

It was incredibly monotonous. Until something caught Shiro’s eye. 

Something only he could have seen. A connection between where ships were being sent and when gladiatorial fights were being scheduled. 

In retrospect, he was always meant to have seen it. It was the first breadcrumb in a trail of bait meant especially for him. That breadcrumb led them to discover a garbled transmission, a distress signal from a lost Altean settlement. A place where something had gone terribly, terribly wrong. 

"If there are Alteans who survive," Kolivan told them, "then we have an obligation to try to help them. But this needs to be done by someone who doesn't look Galra. If it really is an Altean colony, there's a good chance they'll shoot Galra on sight." 

Shiro glanced at Keith, seeing the determined look in his eye. "We're in," he answered for them both. 

Kolivan huffed. "You, Black Paladin, may be our ally, but you are not one of our operatives. Keith goes alone." 

Keith shook his head. "I need Shiro on this." 

"We can't afford to risk _two_ of the Paladins of Voltron," Kolivan rumbled. 

"If we lose even one Paladin," Keith pointed out, crossing his arms, "we won't be able to form Voltron. If the universe can spare me for this, it can spare him, too. I need Shiro." 

Shiro was just glad that Keith didn't see him as a liability. Keith had grown up so much since the Garrison. He was so confident now, so... beautiful. He'd looked up to Shiro once upon a time, but now, Shiro thought it wouldn't make sense for him to. 

How could Keith look up to him now? After everything Shiro had done and experienced in the arena. After what it had made him into. A man who woke up in the night, shaking, and found that the nightmare wasn't gone, it was still written all over his body. A man afraid of his own arm. Afraid of his own mind. 

But if Keith needed him, he'd be there. 

Kolivan eyed them both. 

"Return home safe," he told them at last. "Remember that the universe needs you. In this one instance, your lives are worth more than your mission." 

* * *

They followed the distress call to a space station. It was large, and would have represented a significant settlement if it had been full, but it looked somehow abandoned, even with the lights in the docking area blazing brightly, and the bustle of motion through the ports as they approached. Or perhaps not abandoned, but… forsaken was the word that jumped to Shiro’s mind. 

As soon as they docked, the Alteans crowded up frantically into the shuttlepod, all talking at once. 

A blond woman was speaking frantically about Prince Lotor and how he'd died tragically when his quintessence experiment had gone catastrophically wrong. A boy with similar features headed straight for the front, urging them to depart. But mostly there was pleading. 

"Please, take us with you!" 

The words crowded them, made it impossible to think. Shiro felt as if he were trying to walk through mud, making sense of them in his mind. 

"But the longer you wait," said the blond woman, "the more chance you'll be stuck here. Whatever came out of the rift... it drains ships of power." 

The boy made an angry noise. "Let's not waste time talking this time!" He made to grab Keith's arm where it still gripped the control sticks. 

Keith raised a palm and forcefully pushed him away. The boy’s eyes glinted with defiance, and he drew a weapon. 

The next moment, all Shiro knew was that cold, adrenaline-sharp knowledge that he was fighting for his life. Instinct, muscle memory, the fighting skills that had become hard-wired into his body were too easy to surrender to. This, he knew all too well. Survival through violence was what he'd become. He took down his foe. 

He didn't notice at first when following the dictates of his instinct turned to following something else. He knew only that his grip around his foe's throat was necessary, that walking into the station and towards its central core was the way to survive. 

Keith's words sounded as if he were hearing them from underwater. 

"Shiro! Shiro, where are you going?" 

"To the Komar," Shiro answered mechanically. Of course he was going to the Komar. 

There was a long pause before Keith yelled, "Why?!" 

Shiro stumbled to give a meaningful answer. Wasn't it obvious? "The Komar is hungry." 

There was a growl in Keith's voice, then, that Shiro had never heard before. "Shiro. Tell me what's happening or so help me I will knock you down and _make_ you talk." 

Shiro blinked, and dropped the boy's limp body. 

None of this was obvious. Or... it shouldn't have been. 

"It's speaking to me," he realized. 

"What?" 

Things were sliding slowly into place in his head, as he searched for them. "The Komar." 

"What?" Keith stammered. "Shiro, what is the Komar?" 

Shiro found the shape of the mass in his mind, and pushed a little, to see what he could find. Nothing was hidden from him, not really, though the Komar acted like a heavy blanket, weighing down and slowing thought. 

"It's not... it's not from this reality. It's not quite alive, but it is hungry. It needs quintessence but it needs us to bring its victims closer. It needs... the Champion." 

The Komar had brought them here, Shiro realized, distantly and far, far too late. 

“How do you know this?” Keith asked, worry and skepticism warring in his tone. “Are you sure?” 

Shiro thought about this, and sighed. “I haven’t felt sure about anything lately,” he said. “But there’s something in my mind that’s not me. If I don’t know that right now, I don’t know anything.” 

"If we give it what it wants," Keith asked, watching his face carefully, "will it let us go?" 

"What?" Shiro asked, startled. 

"You heard Kolivan. Our lives are more important than this mission. Our lives are more important than their lives. We need to do whatever we have to to get back. _Whatever_ it takes." 

The conviction in Keith's voice was incredible. 

"A bargain?" Shiro asked. "With the Komar?" 

"Listen. If it doesn't agree, it will have nothing. I'll kill everyone on this station before I let it have its way with you, Shiro, so just let me know how much it will take to get it to let you go." 

"To let _us_ go." 

"That's what I said." 

It hadn't been. Shiro could read between the lines, because the message practically shouted itself out. 

The suggestion that they kill every Altean on this space station in order to save themselves, the implication that Keith would destroy himself in every way before he let Shiro go the same way? It should have been too much. 

Shiro wasn't sure if it was. 

He considered if the idea would even work. Trusting the Komar to keep its word on something like this seemed supremely unwise, but then, Shiro was inside of it as much as it was inside of him. 

Shiro thought the question. And after a moment, he thought he had an answer. 

"It would let us go." 

"So?" Keith asked, like it was simple. 

"So I'm thinking about it." 

He was thinking about it. Of all the principles he'd been taught as a child and as a cadet, honor and peace and justice. Right now, they all felt so far away. As far away as Earth was right now. 

Shiro felt like his soul was slipping away. 

Keith reached out, squeezing his shoulder, a solid, grounding touch in a moment when nothing else felt real. 

"We didn't start this war," he said. "But someone has to finish it." 

"I've done enough of killing people just to save myself," Shiro told him. "More than enough, in the ring." 

"Then we kill," Keith said, voice low and steady, "to save each other. You think you can do that?" 

Shiro looked at Keith. Keith, who was fire that consumed all of Shiro's doubts and worries. Keith, who made everything sound simple when he spoke. Keith, who had always been worth breaking rules for. 

"For you?" Shiro answered. "Of course." 

"Then," said Keith, "you should know you snapped this kid's neck. He's as good as dead. I vote we give him to the Komar." He hefted the body. "Lead the way." 

* * *

It wasn't like they didn't _try_ to find other ways to escape. 

One of the Alteans, who had dark skin and whose gender couldn't immediately be read, sought them out. 

They held their hands up. "I'm not here to fight. I don't have any weapons. I just want to see if there's any way we could pool our resources and escape this place together." 

"Our ship's lost power," Keith said. "I don't know what other resources you think we have." 

"Your weapons," they said. "The sword that changes shape and the arm that burns. They have energy, even if your ship doesn't." 

Keith shook his head. "The sword takes energy from me to change its shape." 

"But the arm?" The Altean looked pointedly at Shiro. 

Shiro looked down at his arm. It was still working, even if the shuttlepod wasn't. 

"It's possible," Shiro admitted. "I wouldn't know how. I'm not an engineer." 

"I am," said the Altean. "Here, just let me..." 

One of the Altean's hands went for a pocket, the other darted out towards Shiro's prosthetic arm. 

Shiro didn't even have time to be shocked before Keith's blade appeared, protruding through their chest. 

"I think they just wanted to look," Shiro said, attempting to reassure, to wipe some of the dark look off of Keith's face. 

"That could have been a weapon," Keith responded. "And they should have asked." His voice hissed in a way Shiro couldn't interpret. 

Shiro peered more closely at Keith's face. His eyes had gone yellow, more Galran. His hands, as he withdrew his blade from the body, were clawed. 

Keith's Galra side. He'd never seen it before. He wondered what kind of emotion it took to bring it out. 

"Are you all right?" he asked. 

Keith just gave him another dark look. "They don't get to touch you," he said with finality. 

Shiro didn't think he would have reacted well to an unexpected touch on his prosthetic. The Altean most likely would have wound up dead, anyway. At least this way Shiro didn't have to be pulled back to the gladiator pits again in his mind. 

"Okay," he said. 

* * *

It happened too many times. 

They'd encounter one of the Alteans, and even if Shiro had wanted to spare their lives, the Alteans wanted to stop them, or wanted revenge for their fellows who had already fallen. 

It was too easy. 

The only time it didn't feel too easy was when one of them somehow got Keith by the throat. Shiro's robot hand shot out and sliced their arm away from Keith with barely a thought. His flesh hand followed, reaching for the Altean's neck, while he wondered if they would like to know what it felt like to be choked. 

That wasn't strange anymore. That was just how the universe was. And Earth was far, far away. 

But as long as Keith was beside him, then that was okay. His cold soul had a fire to reach for. 

* * *

As they walked the cold corridors, emptier by the hour, Shiro once again felt the word “forsaken” was the appropriate one to describe the place. Shiro thought he’d go over the edge if he couldn’t hear something soon that wasn’t their footsteps or their breath. 

Keith’s voice broke in, steadying, even if his words were not. "If I'm remembering correctly," he said, "there's only one Altean left." 

"Yes," Shiro agreed. The Komar was constantly aware of all of them, and now all that attention was focused on a single point. "And he's coming for us." 

They were both silent for a moment, assessing their situation and possible plans. 

"I hate to say it, Shiro," Keith said at last, "but I think the best way to do this is to use you as bait." 

* * *

They positioned Shiro in a room that held a stockpile of tools, most of them useless without quintessence to power the machinery they would have been used for. Part of Shiro's mind was actually on the tools, checking to see if there were any possible exceptions. 

The rest of his mind wandered, thinking of who he'd become, and who Keith had become, and how futile it seemed to be to fight that. Who they were was what had let them survive this long out here, in the hostile and alien reaches of space. 

Keith had always been angry, always prone to violence, but now he seemed to do the same things with purpose, with intent. Now that he knew he was part Galra, it was as if he'd given himself permission to act how he wanted to, and not conform to some more human standard. 

Maybe human standards were overrated. 

Maybe he shouldn't have been letting his thoughts drift, but it was difficult to stay on guard and still look relaxed, like nice tempting bait. Shiro didn't have the knack for it. So he didn't try. 

Shiro wasn't afraid. Not with Keith watching his back. 

In the end, Shiro almost missed it when the last Altean came up behind him, and Keith pounced. But something, and Shiro wasn't sure what it was, prompted him to turn and look just as Keith's flying leap propelled his boot into the Altean's side. 

The Altean rolled and blocked Keith's sword strike, so Keith struck with his other hand, fingers turned to claws plunging deep into the meat of the Altean's belly and ripping him open. 

By the time Shiro had made his way over to them, Keith had pulled the Altean's cloak across his mutilated torso and was wiping his bloody hand with it. 

Carrying this nameless man to the Komar had a ceremony to it that none of the others had had. This was the moment when they would find out if it had all been for nothing. 

This time, they stayed and watched as the Komar drained him, and he turned shriveled and grey. 

Then, Shiro knew that their moment had come, and they had to take it while the Komar was feeling well-fed. "The shuttlepod," he told Keith sharply, and started off at a run. "Now." 

They stumbled through the hatch, and Keith booted the controls, hands moving quicker than humanly possible. Starting the engines, sealing the hatch, unlocking from the airlock and pushing away. 

Once they were clear of the airlock, they turned to look at each other, relief and exhaustion and a muddle of other emotions passing between them. After a moment, Keith set the autopilot, and stood up to move towards Shiro. 

"What are you thinking about?" Keith asked. 

Shiro wanted to be honest. "The way you took down that last Altean," he said. 

"Oh," Keith said, a sliver of doubt starting to creep into his expression for the first time since all this had started. "Did you see that?" 

"It was hard to miss," Shiro said, giving a weak smile. 

"Too much?" Keith asked gravely. 

"No, Keith," Shiro said with quiet awe. "You're never too much." 

Something dark and hungry was in Keith's eyes, and that yellow tinge was back. "Good," he said, "because you're mine, do you understand?" 

Keith was a fire that consumed everything that Shiro was, but Shiro still wasn't sure what it was exactly that Keith wanted from him. 

"I don't," he said. "I don't understand. Tell me, Keith. I want to understand." 

Keith stalked closer, yellow eyes locked on Shiro's at first, then, not losing any of its intensity, that gaze went lower, and Shiro could almost feel the heat of it on his neck, on his chest. Lower than that. 

When Keith finally spoke again, he was close enough that Shiro could hear him whisper. "I'm going to be the only person who ever gets to touch you." 

Shiro shivered. 

Keith looked him in the eye again, waiting for some other response. Shiro could only think of one. 

"Tell me more." 

Keith pushed him down into one of the shuttlepod's seats and planted one knee between his legs before leaning down. 

The kiss was hard, more a push than a caress, and at the same time Shiro could feel his fingers turn into claws as they scratched across his scalp. Keith's fingers made their way higher, twisting into the longer hair at the top of his head. Keith pulled, then, tilting Shiro's head, looking into his eyes with his fierce yellow ones. 

"Listen to me," Keith said in a tone of intimate command. 

"Always." 

"You belong to me, Shiro." 

Shiro's answer was hardly more than a breath, abrupt, as if it had been punched out of him, but Keith seemed to think it was sufficient. 

One more kiss, but it didn't linger it all. Keith held him back, seemingly just looking at him, assessing, as he would have looked at a hoverbike after getting it out of storage, making sure it was still fit to ride. 

Somehow Shiro liked that idea. "Please." 

"Still not too much?" Keith asked. 

"Still not enough." 

That seemed to undo the last of Keith's self-restraint. Keith climbed bodily into his lap, kissing him deep and rough with just a hint of Galran fangs. He reached for Shiro's vest to undo it, then pulled up his shirt. The heat of his hands burned like a brand. One rested over Shiro's heart. The other traced the lines of his torso, following them up to his shoulders, to his neck. 

"Tell me," Shiro begged. 

The claws of Keith's hand dug into the skin over Shiro's heart just a little, and Shiro remembered what he could do with those claws. 

"No matter where you go," Keith whispered into the skin just below Shiro's ear, lips brushing across his neck, "no matter how far you fall, I'll follow you. I'll be right there." 

Shiro gripped Keith's hips with both hands, pulling him closer. "Yes," he hissed. 

Keith hummed in approval, and pressed himself against Shiro from groin to chest, nipping the line of his jaw with sharp teeth. "To hell and back. I swear, Shiro." 

Shiro panted, wanting more, but not wanting to break the contact they had. "Yeah, Keith. I'm yours. Make me yours." 

"Is that what you want?" Keith's voice had gone husky, and he rocked just a little where he sat in Shiro's lap. "To be owned? To be _had?_ " 

Shiro whined. 

"Answer," Keith commanded. 

"Yes," Shiro managed. "Take me." 

Keith gave a pleased, hungry growl and rolled his hips harder this time, licking and worrying at Shiro's neck. He was definitely leaving a mark. He might have been drawing blood. 

Shiro didn't care. If Keith wanted him as a chew toy, then that's what he'd be. 

"Tell me how you want me," he said. 

Keith's eyes were slitted and content, now, as they roamed over Shiro. Still dark with want, but calmer. "I'll have your ass later," he promised. "Right now I think I'll fuck your mouth." He shifted so that his knees were balanced on the arms of Shiro's seat, and his hips filled Shiro's field of vision. 

Shiro made a soft, breathless noise, and leaned forward to mouth at the bulge in the front of Keith's pants. Keith moaned, pressing into it, then fumbled open his button forcefully. Shiro wasn't sure, but he thought he heard a stitch pop somewhere. That didn't matter, though. Nothing mattered but Keith's dick in front of him, beautiful and hard and just waiting for his mouth. 

Shiro let his mouth fall open, and sure enough, Keith pushed in, using him, arms braced against the back of the seat and moaning in a tangled series of noises that meant nothing, and everything. 

Shiro was overwhelmed. 

Keith was everywhere, in front of him and above him and inside of him. The taste of Keith was on his tongue and the hardness of him was in Shiro's throat. Shiro took it gladly, rode through it, taking breaths when he could and clinging to Keith's hips to soften the impacts when it became too much. Moaned around his bulk because too much was exactly what Shiro needed. 

"Ah, Shiro," Keith said, voice breaking. "Yesss. Fuck. All mine." 

Shiro hummed in agreement, and started working his tongue along Keith's length as Keith's strokes grew shorter and more urgent. Shiro swallowed, wanting to know what other noises he could get Keith to make. 

Shiro was not disappointed when the results were mostly his name, over and over, sometimes reverent, sometimes fierce, sometimes broken. Or when he pulsed, thick and hot, into Shiro's mouth with a growl that was not quite human. Shiro swallowed gratefully, and listened to the gasps and tiny moans that resulted. 

When Keith finally pulled away, sinking into the next seat, he looked like some lofty emperor of excess sprawled on his throne. Powerful, comfortable and utterly spoiled. It was how Keith should look all the time, Shiro found himself thinking. 

Shiro tried to adjust himself, get more comfortable, and almost whited out and came right there. 

Keith turned to look at him when he heard Shiro gasp. "Mmmm. Are you going to come in your pants if I don't help you with that?" 

Shiro gave a breathy laugh. "Maybe." 

"I'm torn. It'd be flattering. But messy." Keith made a thoughtful noise. "Okay, how about this. Open those up, let me watch you touch yourself." 

Keith, soft and satisfied, human eyes slitted and round fingertips playing lazily across the skin of Shiro's arm, was beautiful in a way that was so different from the fierce Galra Keith, but still Keith, and still predatory, in its own way. And the heat of his fingertips still burned against Shiro's skin. 

Fuck, Shiro needed to come. 

He fumbled with the fastener of his pants, hissed as his manipulations thrilled and hurt in equal measure. Gasped and sobbed as his cock finally escaped. 

"So pretty," Keith murmured. His fingers trailed down Shiro's wrist, as if giving directions. Shiro shivered again. 

He was almost afraid to touch his cock, knowing how intense it would be right now. But he was Keith's toy to play with, and Keith wanted to see. 

He brushed the underside with his fingers, and gasped so sharply it hurt his chest. Then he closed his hand and swept upwards, and he couldn't breathe for a moment, but then his voice grew from a tremor in his belly and built until it came out his throat as a scream. 

Keith made a small, pleased noise and threaded his fingers between Shiro's, around Shiro's cock. Then he squeezed, just a little too firm. 

The noise Shiro made was not quite protest. 

Keith's fingers slipped away again, and it was as if Shiro now had permission to do what he had to, to come. He worked himself roughly, gasping and shuddering, and the intensity of it was incredible, but somehow he was still surprised when he came, sudden and sloppy, over his hand. He gripped himself, making everything too much and loving it utterly, and moaned low and agonized, and then punctuated it with the name, "Keith." 

"Mmm," Keith agreed. "Yes." 

Shiro groaned again, wiggling just enough to loosen all his tired muscles, and pulled his messy hand away, suddenly not sure what to do with it. 

Keith tutted as he looked on. "Don't waste that. It's mine, remember." 

Shiro offered up his hand, and Keith licked it clean, thoroughly, methodically, and filthily. Shiro was utterly spent, but at that moment, he never wanted Keith to stop touching him. 

Barely a minute later, an explosion rocked the shuttlepod. 

Shiro frowned. "What was that?" 

"Don't worry about it, Love," Keith told him, petting his hair. "Just the station blowing up." 

"You set explosives?" 

"I couldn't tell you. I was afraid the Komar knew whatever you knew." Keith sighed, pressing his face into Shiro's hair, breathing in. "The Komar touched you in ways that no one but me ever should. So I blew it up. It will never feed on anyone ever again. Mission accomplished." 

Shiro contemplated that for a moment. 

"Thank you," he said. 

Keith smiled softly at him. "Any time." 

Shiro slouched further into his seat and slept. He didn't dream. 


End file.
